The organism is intrinsically resistant to numerous antibiotics. Cotrimoxazole is sometimes used, but there is a relatively high level of resistance to this agent. Ceftazidime (Glazidim®, a cephalosporin) is at present the treatment of choice. Ceftriaxone (Rocephine®) or doxycyline can also be used, but are somewhat less active. Imipenem in combination with cilastatin (Tienam®) is an alternative. At present nothing is known about the activity of new antibiotics such as linezolid (Zyvox®). The optimal duration of treatment is not known, but often takes several months. Relapse can occur after several years, especially during immunosuppression.